fix: the delete wallet screens name the wallet's own key material (closes #529)

DeleteWallet and DeleteWalletLostPassword told key and xprv wallets that
their recovery phrase was the way back, but those wallets have none. Both
screens now name the recovery phrase, the private key or the extended
private key, according to the wallet's kind.

The noun comes from keyMaterialName() in the popup view helpers, which
DeleteAddress now uses too in place of its own two-way choice, so these
three screens get it from one place. The lost-password screen's route-back
sentence is reworded to fit all three kinds.

Model: opus-5-5

src/popup/views/deleteAddress.js

@@ -17,9 +17,9 @@ const {
     attachCopyHandlers,
     addressHoldsFunds,
     balanceLinesForAddress,
+    keyMaterialName,
 } = require("./helpers");
 const { formatAddressTotal, getAddressValue } = require("../../shared/prices");
-const { walletHasRecoveryPhrase } = require("../../shared/wallet");
 const { state, saveState } = require("../../shared/state");
 const {
     canRemoveAddress,
@@ -54,9 +54,7 @@ function setFlash(msg) {
 // The noun follows the wallet: an xprv wallet holds no recovery phrase, and
 // this screen is offered on xprv wallets too.
 function recoveryPathText(wallet) {
-    const secret = walletHasRecoveryPhrase(wallet)
-        ? "recovery phrase"
-        : "extended private key";
+    const secret = keyMaterialName(wallet);
     return (
         "Getting the address back into this list is not easy, so be sure. " +
         "Adding an address derives the next unused one, not this one, and " +